Infrastructure-based wireless networks, such as cellular networks or satellite networks, typically include a communications network with fixed and wired gateways. Many infrastructure-based wireless networks employ a mobile unit or host which communicates with a fixed base station that is coupled to a wired network. The mobile unit can move geographically while it is communicating over a wireless link to the base station. When the mobile unit moves out of range of one base station, it may connect or “handover” to a new base station and starts communicating with the wired network through the new base station.
In comparison to infrastructure-based wireless networks, ad hoc networks are self-forming wireless networks which can operate in the absence of any fixed infrastructure, and in some cases an ad hoc network is formed entirely of mobile units. An ad hoc network typically includes a number of geographically-distributed, potentially mobile units, sometimes referred to as “nodes,” which are wirelessly connected to each other by one or more links (e.g., radio frequency communication channels). The nodes can communicate with each other over a wireless media without the support of an infrastructure-based or wired network.
A mesh network is a form of an ad hoc wireless network based on autonomous collections of mobile nodes that communicate with each other over wireless links having limited bandwidths. Individual nodes in a mesh network can perform routing functions, which enable a mesh network to be reconfigured around blocked paths or poor connections by “hopping” from one node to another until a destination is reached. A mesh network is thus described as self-healing, as it can still operate effectively even when particular nodes break down or leave the network.
As wireless communications networks such as mesh networks become more prevalent, security continues to be a major concern to both communications network providers and end users. In a wireless communications mesh network the security environment can offer the greatest challenges since data may be readily received and manipulated by many nodes. The radio links used in a wireless communications mesh network expose signaling and other data traversing the network to eavesdroppers and/or would-be hackers. In a multi-hop wireless communications mesh network, this requires each link between the meshed devices to have a unique security association established through a multi-hop authentication and key management process. Frames sent over-the-air on the link then can be protected with established security associations.
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